Biochemical Changes in the Connective Tissue Pocket

When films of plastics or metals are imbedded s.c. in rodents, the material becomes enveloped by a connective tissue pocket wherein tumors may eventually appear. Biochemical studies were made on this tissue at different intervals after imbedding. These included assays for lactate, malate, and glucose-6-phosphate dehydrogenase activities; determinations of DNA; and analyses for soluble and insoluble collagen. It was found that the activities of the 3 enzymes were highest at one month after imbedding and then decreased markedly. On the other hand, the nucleic acid concentration either remained constant or decreased to a small extent. The soluble collagen was elevated at the early stages and decreased to a significant degree, while the insoluble collagen increased with time until a maximum was reached. Subsequently, the latter either remained constant or decreased slightly. The possible relationship of these changes with the ultimate appearance of tumors is discussed.